Epidural anaesthesia and low back pain after delivery: a prospective cohort study.

OBJECTIVE: To determine whether epidural anaesthesia during labour and delivery is a risk factor for postpartum back pain.

DESIGN: Prospective cohort study with follow up at one day, seven days, and six weeks after delivery.

SETTING: Teaching hospital in Montreal.

SUBJECTS: 329 women who delivered a live infant(s) during the study period. Exclusion criteria were back pain before pregnancy and delivery by elective caesarean section.

INTERVENTION: Epidural anaesthesia during labour and delivery.

MAIN OUTCOME MEASURES AND RESULTS: The primary outcome variable was development of postpartum low back pain. Back pain was quantified with self reports (yes/no), a pain score (numeric rating scale), and degree of interference with daily activities. Of the 329 women, 164 received epidural anaesthesia during labour and 165 did not. The incidence of low back pain in epidural v non-epidural group was 53% v 43% on day one; 21% on day seven; and 14% v 7% at six weeks. The relative risk for low back pain (epidural v non-epidural) adjusted for parity, delivery, ethnicity, and weight was 1.76 (95% confidence interval 1.06 to 2.92) on day one; 1.00 (0.54 to 1.86) on day seven; and 2.22 (0.89 to 5.53) at six weeks. There were no differences between the two groups in pain scores or the frequency of interference with daily activities. Similar results were obtained in the subgroup of women with low back pain of new onset--that is, those women with no back pain during their pregnancy.

CONCLUSIONS: Postpartum low back pain was common but decreased considerably over the short term. The association between epidural anaesthesia and postpartum low back pain was inconsistent over time with a significantly increased risk of low back pain (epidural v non-epidural) noted only on the first day after delivery.